Process for the production of iodates



Patented Apr. 14, 1931 UNITED STATES PATENT GFFIGE HEINRICH HEIMANN AND HANS-BERNHARD SEEBOEM, OF DESSAU' IN .ANHALT, GER- MANY, ASSLGNORS TO I. G. FARBENINDUSTRZE AKTIENGESELLSCHAFT, OF FRANK- FORT-ON-THE-MAIN, GERMANY, A CORPORATION OF GERMAN Y PROCESS FOR THE PRODUCTION OF IODATES No Drawing. Application filed September 12, 192$, Serial No. 305,607, and in Germany October 28, 1927.

The present invention relates to the production of alkali metal by the direct oxidation of alkali metal iodides.

For this purpose according to the invention alkali metal iodides are treated with oxygen, for instance with atmospheric air, at a raised temperature above 300 C. but below 550 (1, more especially at 4100-550 C. in the presence of an alkali metal hydroxide and a metal oxide, for example aluminum oxide or a heavy metal oxide, such as bismuth oxide or a mixture of several metal oxides.

The reaction takes place at ordinary atmospheric pressure, so that it is generally superficient to elevate the pressure. The process may be carried out by melting an alkali metal iodide, i. e. potassium iodide with an alkali metal hydroxide, i. e. potassium hydroxide containing a little amount of a metal oxide, i. e. aluminum oxide or bismuth oxide, and passing air over the melt heated to about 500 C.

When heating the melt to about 600 0., the previously formed io-date by a known reaction is decomposed giving off oxygen and forming the corresponding iodide. This reversible reaction is a basis for a production of oxygen; the regenerated iodide may be transformed again into the iodate by the process according to the invention.

Example 1.-An air current is led over a melt of 3 parts by weight of potassium hydroxide and 1 part by weight of potassium iodide kept at a temperature of about 525 0., the melt containing 1 per cent. of bismuth oxide. In the course of one hour per cent. of the theoretical amount of potassium iodate are formed. Then the temperature is raised to 600 C. the melt gives off oxygen and there remains only 5% of iodate calcu lated on the quantity of alkali metal iodide used as starting material.

Ewample 2.A current of air is led over a melt of 3 parts by weight of potassium hydroxide and 1 part by weight of potassium iodide kept at a. temperature of about 450 C., the melt containing 4 per cent. of aluminum oxide. In the course of one hour 50 per cent. of the theoretical amount of potassium iodate are formed. lVhen the temperature is raised to about 575 C. the melt gives off oxygen and thereafter contains only 15 per cent. of iodate calculated on the quantity of alkali metal iodide used as starting material.

What we claim is 1. The process which comprises bringing an alkali metal iodide into contact with oxygen at a temperature between about 300 and 550 (1., at a pressure not substantially excee'ding atmospheric pressure, in the pres ence of an alkali metal hydroxide and a metal oxide of the group consisting of aluminum oxide and bismuth oxide.

2. The process which comprises bringing an alkali metal iodide into contact with oxygen at a temperature between about 400 and 550 (1, at a pressure not substantially exceeding atmospheric pressure, in the presence of an alkali metal hydroxide and a metal oxide of the group consisting of aluminum oxide and bismuth oxide.

3. The process of producing oxygen which comprises bringing an alkali metal iodide into contact with air at a temperature between about 300 and 550 C. and at a pressure not substantially exceeding atmospheric pressure, in the presence of an alkali metal hydroxide and a metal oxide of the group consisting of aluminum oxide and bismuth oxide and raising the temperature of the melt to about 600 C.

In testimony whereof, we affix our signatures.

HEINRICH HEIMANN. HANS-BERNHARD SEEBOHM.

CERTIFICATE OF CORRECTION. Patent No. 1,800,630. Granted April 14, 1931, to

HEINRICH HElMANN ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 2, after the word "metal" insert the word iodates; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 26th day of May, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

